<template>
  <h2>当前求和为：{{sum}}</h2>
  <button @click="sum++">点我+1</button>
  <hr>
  <h2>当前的信息为：{{msg}}</h2>
  <button @click="msg+='!'">修改信息</button>
  <hr>
  <h2>姓名：{{person.name}}</h2>
  <h2>年龄：{{person.age}}</h2>
  <h2>薪资：{{person.job.j1.salary}}K</h2>
  <button @click="person.name+='~'">修改姓名</button>
  <button @click="person.age++">增长年龄</button>
  <button @click="person.job.j1.salary++">涨薪</button>
</template>
<script>
import {ref,reactive,watch} from 'vue'
export default {
  name: 'Demo',
  setup() {
    // 数据
    let sum = ref(0)
    let msg = ref('你好啊')
    let person = ref({
      name: '张三',
      age: 18,
      job: {
        j1: {
          salary: 20
        }
      }
    })

    watch(sum,(newValue,oldValue)=>{
      console.log('sum的值变化了',newValue,oldValue)
    })

    watch(person.value,(newValue,oldValue)=>{
      console.log('person的值变化了',newValue,oldValue)
    })

    // 返回一个对象（常用）
    return {
      sum,
      msg,
      person
    }
  }
}
</script>
